The "Full House" star appeared on "TODAY" Wednesday morning, where he confirmed he had been diagnosed with stage 3 non-Hodgkin lymphoma ... a type of blood cancer that starts in the lymphatic system.

While speaking with Hoda Kotb about his diagnosis, the actor revealed he received the diagnosis 5 weeks ago ... which prompted him to undergo 3 surgeries and receive several rounds of chemotherapy.

Per Dave, he has B-cell lymphoma ... a "very aggressive type of lymphoma."

He added ... "It happened very quickly. The onset of this growing lymphoma in my groin area was very quick. So, I said, 'Eh. something's not right. I have a golf ball down here.'"

From there, Dave said his doctors biopsied the growth, discovering his cancer status. The TV star shared he did get a positive update in his cancer battle, however ... with his medical team informing him his cancer hadn't spread.

He continued ... "At that point, the curability rate went up to 90-plus percent. So, it's very treatable."

Dave also opened up about his health journey with People, where he shared he first clocked swelling in his lymph nodes after an upper respiratory infection. The funny man admitted the diagnosis was "pretty overwhelming," given the fact he went from "a bit of a head cold to ... cancer."

He said he's leaning on his wife, Melissa Bring, family, and friends in the medical field to tackle the disease "head-on."

Later, on his podcast "Full House Rewind with Marla Sokoloff," Dave explained his decision to keep a positive mindset amid his cancer journey ... saying he wanted to be "strong" for his family.

He shared ... "I have my good days. I have my bad days. Some days are nauseous and dizzy, and then there's other days where the steroids kick in, and I feel like I have a ton of energy."